Humidifier



P 1969 b. c. WELLMAN 3,464,400

HUMIDIFIER Filed NOV. 15, 1967 INVENTOR. DONALD C. WELLMAN.

ATTORNEY.

United States Patent US. Cl. 126-113 4 Claims ABSTRACT OF THE DISCLOSURE A humidifier adapted for use with a forced air furnace having a thermally operated water supply valve to regulate the flow of water to be evaporated.

BACKGROUND OF THE INVENTION Humidification of air in homes and other structures is often necessary during the heating season. When the area being conditioned is heated by a warm air furnace, it is common practice to combine a humidifier with the furnace to provide moisture in the warm air stream supplied to the area being conditioned. Ordinarily, the humidifier must be supplied with a source of water to be evaporated and a control to provide humidifier operation when the furnace is operating. If the humidifier is controlled by opening and shutting a valve in the water supply line to the humidifier, an electrical solenoid valve connected in parallel with the furnace fan switch can be utilized to provide a flow of water to the humidifier when the fan is operating. This adds to the expense of the humidifier installation since the humidifier must be wired to the furnace electrical system.

Use of a water valve responsive to the temperature of air in the discharge plenum has been suggested to simplify installation of the humidifier. However, in normal operation of a forced warm air furnace when the room thermostat controlling the furnace is satisfied, the burner will shut off and the fan will continue to run until the furnace heat exchanger cools down to a pre-selected temperature. When the fan shuts off, the residual heat in the heat exchanger raises the plenum temperature which would turn on the valve when there was no air flow through the furnace and thus such installation is not adequate.

SUMMARY OF THE INVENTION This invention relates to a humidifier for use with a forced air furnace, the humidifier including a thermally actuated valve responsive to the temperature of the air discharged from the furnace when the furnace fan is operating to regulate discharge of water in a heated air stream.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a perspective view of a humidifier with parts broken away for clarity;

FIGURE 2 is a sectional view of the humidifier; and

FIGURE 3 is an enlarged sectional view of the portion of the humidifier containing the thermally actuated water valve.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, there is illustrated a humidifier casing 2 having an inlet 5 and an outlet 7 for passage of heated air as shown by the solid arrows from the hot air plenum through an evaporative pad 9 in the casing to the return air duct of a forced air furnace. The air flow through the casing can also be reversed as shown by the dotted arrows. The air flow arrangement provides humidified air to the furnace return air plenum for passage through the furnace and the warm air distribution system to the area being conditioned. While this arrangement results in a portion of the heated air by-passing the normal air distribution system, it provides a positive pressure differential across the humidifier casing to assure a relatively constant air flow therethrough.

Water to be evaporated is supplied to the humidifier through line 11 and thermally controlled water valve 13. In the preferred embodiment of the invention, the valve 13 is provided with a thermal responsive element 14 which is adapted to open the valve in response to warm air passing thereover to allow passage of water to the humidifier. Water from the valve 13 is supplied to jet pump 15. Water from jet pump 15 flows through line 17 to upper reservoir 19 which is provided with a dumping siphon 21. When the water level in the upper reservoir 19 reaches the top of siphon 21, the water is siphoned into a distribution tray 23 which is provided with notches or weirs 25 for distributing the water in the tray evenly over evaporative pad 9 for evaporation by the air stream passing therethrough. Excess water from the pad drains into lower reservoir 27.

A portion of the water in lower reservoir 27 is pumped back to upper reservoir 19 by jet pump 15 which is provided with a pickup line 29 having a strainer 31 associated therewith. The jet pump is so sized that it induces about 3 parts of water from the lower reservoir for each part of water supplied through valve 13.

Even though water in the lower reservoir is being constantly pumped to the upper reservoir, enough water is provided to the humidifier to assure that the water level in the lower reservoir continually rises until it covers the dump siphon 32 associated therewith. When this occurs, the water in the lower reservoir is siphoned to drain, thereby removing collected dirt and scale particles in the reservoir and preventing a high mineral concentration in the recirculating water. Small apertures 33 are provided in both siphons to break the siphonling action at the desired water level to prevent complete draining of the reservoirs while maintaining the end of the siphons near the bottom of the reservoirs to assure removal of dirt particles collecting thereon.

The valve 13 is disposed in housing 40 which encloses the valve on the top and four sides. An opening 42 in the side wall of the humidifier casing and the side wall of housing 40 is provided for passage of heated air from the humidifier casing into housing 40. An opening 44 is provided in the top of housing 40 for passage of warm air therethrough.

Considering the operation of the humidifier in conjunction with a forced air furnace, air flow through the humidifier from the hot air plenum of the furnace to the cold air plenum is provided by the pressure differential created therebetween by the furnace fan.

When the furnace fan is operating, a portion of the warm air supplied to the humidifier casing will escape through opening 42, causing thermally responsive valve 13 to open to provide water to the humidifier. When the furnace fan shuts off, warm air will no longer circulate through opening 42 over valve 13. Natural convection of air through housing 40 and out opening 44 will quickly cool valve 13 and thereby shut off the supply of water to the humidifier.

As can be seen from the foregoing, the present invention provides a thermally controlled humidifier which is adapted to operate at minimal temperatures and therefore provide humidification to the area being conditioned the entire time the furnace fan is operating. Further, the present invention provides a humidifier control which is not affected by a rise in plenum temperature after the fan stops.

While I have described a preferred embodiment of the invention, it is to be understood the invention is not limited thereto but may be otherwise embodied within the scope of the following claims.

I claim:

1. A humidifier for use with a forced air furnace comprising:

a casing adapted for passage of air therethrough from 10 the furnace discharge plenum to the furnace return air plenum,

an evaporative media disposed in said casing for passage of warm air therethrough,

a thermally-responsive valve to regulate the supply of liquid to said media for evaporation therefrom, said thermally-responsive valve being disposed outside said casing so as to be unaffected by the temperature of the air in said casing when the furnace fan is inoperative, said casing being provided with an opening proximate said valve to bleed warm air from said casing over said valve when the fan is in operation.

2. A humidifier according to claim 1 including a housing associated with said valve, said housing being adapted for natural convection of air therethrough, said housing being operatively associated with said casing to allow passage of the bleed air from said casing through said housing and over said thermally responsive valve.

3. A humidifier according to claim 2 wherein said housing includes four sides and a top closure for enclosing said valve, said housing having a first opening in the top closure thereof for passage of air therethrough, said housing having a second opening in a side thereof in substantial alignment with the opening in said casing for passage of warm air from said casing through said housing over said valve.

4. A method for humidifying a conditioned area, served by a forced air heating system including the steps of:

passing a portion of the heated air over an evaporative contact media,

supplying a liquid to the evaporative contact media for evaporation by the air passing thereover,

bleeding a portion of the heated air from the system,

passing the bleed air over a heat responsive control to regulate flow of liquid to the contact media.

Q References Cited UNITED STATES PATENTS 2,043,217 6/1936 Yaglou.

2,075,314 3/1937 Suppes 126-113 X 2,105,773 1/1938 Magney 126-113 x 2,328,538 9/1943 Furlong 126-113 3,265,371 8/1966 McGrath 126-113 x JAMES w. WESTHAVER, Primary Examiner U.S. c1. X.R. 

